Thermoelectric generator : experimental investigation and performance analysis

• Main Author: Tee, Jonathan Li Wei
• Other Authors: Leong Kai Choong
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Mechanical engineering::Energy conservation
• Online Access: http://hdl.handle.net/10356/60355
• Institution: Nanyang Technological University

Discovered in the 19th century, thermoelectric power generation converts heat into electrical power. It was then thought that its low efficiency could not be further improved due to the material’s figure of merit, a material property that controls the efficiency. Presently, due to the global demand for sustainable energy sources coupled with the advancement of technology, new thermoelectric materials with better figure of merit were created and thermoelectric power generation was seen as a viable source to harness waste heat into useful energy. This saw the rise in interest in thermoelectric power generation. With much research put into enhancing the figure of merit, it was later found that enhancing the system architecture of how thermoelectrics are used also played a part in improving its efficiency. One of these methods is to capitalise efficiency gain during transient power generation where the thermal and electric transport are decoupled from the time domain. Little research has been done in this area and hence this project aims to investigate the behaviour of a thermoelectric power generation module during pulsing transient input. An experiment facility was set up, utilising direct heating from a heating block and cooling from a refrigerator circulator while placed in a vacuum. The project was aimed at determining the ideal steady state conditions before advancing to transient state conditions. Various experiments were conducted by varying the heat input and pulsing time. It was discovered the thermoelectric generator (TEG) managed to achieve a maximum efficiency of 8.2%, approximately 3.5 times more than the steady state efficiency of 2.5%. Furthermore, it can be concluded that the larger the difference between the pulsing and recovery inputs, the better the efficiency that was achieved over a longer period of time. During free cooling where the TEG was pulsed between maximum input and no input, an efficiency of 2.3% was achieved. The short duration of higher efficiency gained during the pulsing transient experiments proved that transient power generation is a viable new approach in addition to the increase of the material figure of merit to improve thermoelectric efficiency.